[PATCH] msvcrt: Don't set MXCSR in _control87.

[Myah Caron]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=27594
Signed-off-by: Myah Caron 
---
This appears to match native MSVCRT's behavior, at least the one provided by vcrun6.

I'm not sure if the style is correct (the helper being directly below the __control87_2 comment).
---
 dlls/msvcrt/math.c | 61 +++++++++++++++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 23 deletions(-)

diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index eae917076f..7ad79a07e5 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -1101,6 +1101,41 @@ double CDECL MSVCRT__chgsign(double num)
  * Not exported by native msvcrt, added in msvcr80.
  */
 #ifdef __i386__
+static unsigned int get_flags_from_mxcsr(void) {
+#ifdef __GNUC__
+    unsigned long fpword;
+    unsigned int flags;
+
+    __asm__ __volatile__( "stmxcsr %0" : "=m" (fpword) );
+
+    /* Convert into mask constants */
+    flags = 0;
+    if (fpword & 0x80)   flags |= MSVCRT__EM_INVALID;
+    if (fpword & 0x100)  flags |= MSVCRT__EM_DENORMAL;
+    if (fpword & 0x200)  flags |= MSVCRT__EM_ZERODIVIDE;
+    if (fpword & 0x400)  flags |= MSVCRT__EM_OVERFLOW;
+    if (fpword & 0x800)  flags |= MSVCRT__EM_UNDERFLOW;
+    if (fpword & 0x1000) flags |= MSVCRT__EM_INEXACT;
+    switch (fpword & 0x6000)
+    {
+    case 0x6000: flags |= MSVCRT__RC_UP|MSVCRT__RC_DOWN; break;
+    case 0x4000: flags |= MSVCRT__RC_UP; break;
+    case 0x2000: flags |= MSVCRT__RC_DOWN; break;
+    }
+    switch (fpword & 0x8040)
+    {
+    case 0x0040: flags |= MSVCRT__DN_FLUSH_OPERANDS_SAVE_RESULTS; break;
+    case 0x8000: flags |= MSVCRT__DN_SAVE_OPERANDS_FLUSH_RESULTS; break;
+    case 0x8040: flags |= MSVCRT__DN_FLUSH; break;
+    }
+
+    return flags;
+#else
+    FIXME( "not implemented\n" );
+    return 0;
+#endif
+}
+
 int CDECL __control87_2( unsigned int newval, unsigned int mask,
                          unsigned int *x86_cw, unsigned int *sse2_cw )
 {
@@ -1170,28 +1205,7 @@ int CDECL __control87_2( unsigned int newval, unsigned int mask,

if (sse2_supported)
     {
-        __asm__ __volatile__( "stmxcsr %0" : "=m" (fpword) );
-
-        /* Convert into mask constants */
-        flags = 0;
-        if (fpword & 0x80)   flags |= MSVCRT__EM_INVALID;
-        if (fpword & 0x100)  flags |= MSVCRT__EM_DENORMAL;
-        if (fpword & 0x200)  flags |= MSVCRT__EM_ZERODIVIDE;
-        if (fpword & 0x400)  flags |= MSVCRT__EM_OVERFLOW;
-        if (fpword & 0x800)  flags |= MSVCRT__EM_UNDERFLOW;
-        if (fpword & 0x1000) flags |= MSVCRT__EM_INEXACT;
-        switch (fpword & 0x6000)
-        {
-        case 0x6000: flags |= MSVCRT__RC_UP|MSVCRT__RC_DOWN; break;
-        case 0x4000: flags |= MSVCRT__RC_UP; break;
-        case 0x2000: flags |= MSVCRT__RC_DOWN; break;
-        }
-        switch (fpword & 0x8040)
-        {
-        case 0x0040: flags |= MSVCRT__DN_FLUSH_OPERANDS_SAVE_RESULTS; break;
-        case 0x8000: flags |= MSVCRT__DN_SAVE_OPERANDS_FLUSH_RESULTS; break;
-        case 0x8040: flags |= MSVCRT__DN_FLUSH; break;
-        }
+        flags = get_flags_from_mxcsr();

TRACE( "sse2 flags=%08x newval=%08x mask=%08x\n", flags, newval, mask );
         if (mask)
@@ -1241,7 +1255,8 @@ unsigned int CDECL _control87(unsigned int newval, unsigned int mask)
 #ifdef __i386__
     unsigned int sse2_cw;

-    __control87_2( newval, mask, &flags, &sse2_cw );
+    __control87_2( newval, mask, &flags, 0 );
+    sse2_cw = get_flags_from_mxcsr();

if ((flags ^ sse2_cw) & (MSVCRT__MCW_EM | MSVCRT__MCW_RC)) flags |= MSVCRT__EM_AMBIGUOUS;
 #elif defined(__x86_64__)
--
2.26.2

[Alexandre Julliard]

Myah Caron  writes:
> Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=27594
> Signed-off-by: Myah Caron
>
> This appears to match native MSVCRT's behavior, at least the one provided by vcrun6.

It's not obvious because the tests are in kernel32, but we are
definitely supposed to set it:

../../../tools/runtest -q -P wine -T ../../.. -M kernel32.dll -p kernel32_test.exe thread && touch thread.ok
thread.c:1915: Test failed: expected 0x20301 got 0x80020301
thread.c:1916: Test failed: expected 0x70000c60 got 0x1f800c60
thread.c:1926: Test failed: expected 0x20301 got 0x80020301
thread.c:1927: Test failed: expected 0x70000c60 got 0x1f800c60
make: *** [Makefile:948: thread.ok] Error 4

Looking at your test case, it may be that we shouldn't set it when the
FPU control word didn't change. You should extend the tests in thread.c.

[Myah Caron]

Thank you! I'll extend the test and hopefully also find a solution that mimics Windows's behavior :)

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, July 3, 2020 12:15 AM, Alexandre Julliard  wrote:
> Myah Caron [e-mail] writes:
> > Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=27594
> > Signed-off-by: Myah Caron [e-mail]
> >
> > This appears to match native MSVCRT's behavior, at least the one provided by vcrun6.
>
> It's not obvious because the tests are in kernel32, but we are
> definitely supposed to set it:
>
> ../../../tools/runtest -q -P wine -T ../../.. -M kernel32.dll -p kernel32_test.exe thread && touch thread.ok
> thread.c:1915: Test failed: expected 0x20301 got 0x80020301
> thread.c:1916: Test failed: expected 0x70000c60 got 0x1f800c60
> thread.c:1926: Test failed: expected 0x20301 got 0x80020301
> thread.c:1927: Test failed: expected 0x70000c60 got 0x1f800c60
> make: *** [Makefile:948: thread.ok] Error 4
>
> Looking at your test case, it may be that we shouldn't set it when the
> FPU control word didn't change. You should extend the tests in thread.c.
>
> Alexandre Julliard
> [e-mail]